Device and method for controlling in-vivo pressure

ABSTRACT

A differential pressure regulating device is provided for controlling in-vivo pressure in a body, and in particularly in a heart. The device may include a shunt being positioned between two or more lumens in a body, to enable fluids to flow between the lumens, and an adjustable flow regulation mechanism being configured to selectively cover an opening of the shunt, to regulate the flow of fluid through the shunt in relation to a pressure difference between the body lumens. In some embodiments a control mechanism coupled to the adjustable flow regulation mechanism may be provided, to remotely activate the adjustable flow regulation mechanism.

RELATED APPLICATIONS

The present application is a U.S. national application of PCT Application No. PCT/IL2005/00131, filed on Feb. 3, 2005. This application also claims the benefit under 119(e) of U.S. Provisional Application No. 60/541,267 filed on Feb. 3, 2004 and U.S. Provisional Application No. 60/573,378 filed on May 24, 2004, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to devices and methods for reducing or regulating pressure within a circulatory system, and in particular to regulate blood pressure in a heart.

BACKGROUND OF THE INVENTION

CHF is recognized as one of the most common causes of hospitalization and mortality in Western society, and has a great impact on the quality of life. CHF is a disorder characterized by low systemic perfusion and inefficient cardiac function. CHF causes may include myocardial insult due to ischemia, cardiomyopathy and other processes. Pathophysiologic mechanisms that are directly associated with CHF include reduced cardiac output, increase in cardiac filling pressures, and fluid accumulation, which may lead to, for example, pulmonar congestion and dyspnea. Impairment of systolic function may result in poor left ventricular contraction and reduced cardiac output, which may generate clinical symptoms including effort intolerance, dyspnea, reduced longevity, edema (lung or peripheral) and pain. A patient with systolic dysfunction may usually have a larger left ventricle because of phenomena called cardiac remodeling aimed to maintain adequate stroke-volume. This pathophisiologic mechanism is associated with increased atrial pressure and left ventricular filling pressure. With abnormal diastolic function, the left ventricle may be stiff and markedly less compliant partly because of abnormal relaxation leading to inadequate cardiac filling at normal pressures. Maintenance of adequate cardiac filling at higher filling pressures may be needed to maintain cardiac output. This mandatory rise of filling pressure to maintain cardiac filling and output may lead to pulmonary venous hypertension and lung edema.

Presently available treatments for CHF fall into three generally categories: (1) pharmacological, e.g., diuretics; (2) assist systems, e.g., pumps; and (3) surgical treatments. With respect to pharmacological treatments, vasodilators have been used to reduce the workload of the heart by reducing systemic vascular resistance and diuretics to prevent fluid accumulation and edema formation, and reduce cardiac filling pressure.

Assist devices used to treat CHF may include, for example, mechanical pumps. Mechanical pumps reduce the load on the heart by performing all or part of the pumping function normally done by the heart. Currently, mechanical pumps are used, for example, to sustain the patient while a donor heart for transplantation becomes available for the patient. There are also a number of pacing devices used to treat CHF. Resysnchronization pacemakers have also been used to treat CHF. Finally, there are at least three extremely invasive and complex surgical procedures for treatment of heart failure: 1) heart transplant; 2) dynamic cardiomyoplasty; and 3) the Batista partial left ventriculectomy.

In extreme acute situations, temporary assist devices and intraaortic balloons may be helpful. Cardiac transplantation and chronic left ventricular assist device (LVAD) implants may often be used as last resort. However, all the assist devices currently used are intended to improve pumping capacity of the heart and increase cardiac output to levels compatible with normal life, reducing filling pressures and/or preventing edema formation. Finally, cardiac transplantation may be used to treat extreme cardiac dysfunction cases, however this procedure is highly invasive and is limited by the availability of donor hearts. The mechanical devices may allow propulsion of significant amount of blood (liters/min) and this is also their main limitation. The need for power supply, relatively large pumps and possibility of hemolysis and infection are all of concern.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings in which:

FIG. 1A is a schematic illustration of a Differential Pressure Regulation Device (DPRD), in accordance with an exemplary embodiment of the invention;

FIGS. 1B-1I are schematic illustrations of additional embodiments of Differential Pressure Regulation Devices (DPRD), in accordance with some embodiments of the invention;

FIG. 1J is a chart describing an example of a pressure curve related to the relationship between the change in pressure difference between two lumens, the flow through the flow control mechanism and the orifice area, in accordance with an exemplary embodiment of the present invention;

FIGS. 2A and 2B are schematic illustrations of a cross-section view and a side view, respectively, of an adjustable shunt, tube or other structure in accordance with an exemplary embodiment of the invention;

FIG. 3 is a schematic illustration of a shunt in accordance with another exemplary embodiment of the invention;

FIG. 4 is a schematic illustration of a shunt including a Flow Regulation Mechanism (FRM) in accordance with an exemplary embodiment of the invention;

FIG. 5 is a schematic illustration of the shunt of FIG. 4 and incorporating a FRM in an open state in accordance with an exemplary embodiment of the invention;

FIG. 6 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 7 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 8 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 9 is a schematic illustration of a FRM within a heart, in accordance with another exemplary embodiment of the invention;

FIG. 10 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 11 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 12 is a schematic illustration of a FRM in accordance with another exemplary embodiment of the invention, which may be used, for example, in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or the shunt of FIG. 3;

FIG. 13A is a schematic illustration of an apparatus for remotely controlling a DPRD in accordance with some embodiments of the present invention;

FIGS. 13B-E are schematic illustrations of mechanisms for remotely controlling a DPRD, in accordance with some embodiments of the present invention; and

FIG. 14 is a flow chart illustrating a method of controlling pressure, for example, blood pressure in a heart, according to some embodiments of the present invention.

It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

SUMMARY

The present invention may provide methods and devices for regulating pressure in a body. According to some embodiments of the present invention, a differential pressure regulating device may include a shunt being positioned between two or more lumens in a body, to enable fluids to flow between the lumens, and an adjustable flow regulation mechanism being configured to selectively cover an opening of the shunt, to regulate the flow of fluid through the shunt in relation to a pressure difference between the body lumens.

According to some embodiments the pressure regulating device may include a shunt being positioned between two or more chambers in a heart, to enable fluids to flow between the chambers, an adjustable flow regulation mechanism being configured to selectively cover the opening of the shunt, to regulate the flow of fluid through the shunt, and a control mechanism to be coupled to the adjustable flow regulation mechanism, to remotely activate the adjustable flow regulation mechanism.

In another embodiment a method is provided to control in-vivo pressure, which may include implanting a differential pressure regulation device in a body, the pressure regulation device including a shunt placed between two or more lumens in a body, deploying a flow regulation mechanism, and controlling the flow regulation mechanism setting according to changes in pressure differences between the lumens.

In a further embodiment of the present invention a method is provided to control in-vivo pressure, which may include controlling a flow regulation mechanism flow setting using a control mechanism implanted in a body, the flow regulation mechanism being disposed within a differential pressure regulation device that includes a shunt placed between two or more lumens, for example, between a left atrium of a heart and a right atrium of a heart.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and structures may not have been described in detail so as not to obscure the present invention.

It will be appreciated that although part of the discussion herein may relate, for exemplary purposes, to a heart, heart chambers and/or heart atriums, embodiments of the present invention are not limited in this regard, and may be used in conjunction with various other vessels, lumens, organs or body sites. For example some embodiments of the present invention may include regulating fluid transfer between cavities in the brain, between selected organs, between blood vessels (e.g., between the aorta and the vena-cava) etc., and/or between other suitable lumens, for example, zones, cavities, organs, vessels, regions or areas in a body.

Some embodiments of the present invention include, for example, a method and apparatus for controlling in-vivo pressure by reducing or otherwise controlling pressure differences between two or more body sites, for example, two chambers of the human heart (e.g., the left atrium and the right atrium). For example, such pressure control may be used to help solve the problem of increased cardiac filling pressure in patients with congestive heart failure and predominantly diastolic dysfunction, thereby helping to minimize or prevent pulmonary fluid accumulation, edema formation and clinical complaint of dyspnea. In another example the pressure control may be used to reduce left ventricle filling pressure. Some embodiments of the invention may include a Differential Pressure Regulation Device (DPRD), for example, including a shunt, tube or other structure having an orifice, tube or opening to fluidically connect two or more lumens, for example, to connect a left atrium of a heart with a right atrium of the heart. In accordance with some embodiments of the invention, the DPRD may include an adjustment mechanism or a regulation mechanism, able to adjust, modify or otherwise regulate, for example the cross-sectional area of the orifice, for example, in relation to a change in pressure difference between the first and second lumens, for example, such as to increase and/or decrease the flow-rate of blood between the two lumens.

Some embodiments of the present invention may be used, for example, to unload an excessive filling pressure of a left heart ventricle in a Congestive Heart Failure (CHF) patient, and to potentially prevent or reduce the occurrence of pulmonary edema.

Some embodiments of the present invention include, for example, implanting an adjustable DPRD in a wall between two heart chambers, e.g., between the left atrium and the right atrium. The pressure regulation device may, for example, allow a selective volume of blood to flow from the left atrium to the right atrium, in relation to the change in pressure difference between the left atrium and the right atrium. The pressure regulation device may, for example, be adjusted to selectively change the size or shape of the opening, amount of blood allowed to flow through, etc.

In some embodiments, the pressure regulation device may be configured to maintain a continual flow between two or more lumens, for example, between the left atrium and the right atrium. For example, a shunt, tube or other structure may be coupled to a cover, valve opening, valve stem, or other flow regulation mechanism that may be configured to be continually ajar, to enable a selected minimal quantity of fluid to continually flow between two lumens in a body, for example, between the heart chambers. The cover may be subsequently adjusted, for example may be further opened and/or closed, to control the quantity of fluid flow between the lumens. The fluid flow through the DPRD may increase or decrease in accordance with changes in the pressure or pressure difference between the two lumens. For example, cover may be opened and/or closed as the pressure in the left atrium increases or decreases relative to the pressure in the right atrium. In some embodiments the DPRD may be configured such that the orifice cover has no direct contact with the shunt opening to reduce help minimize or prevent tissue growth on or around the orifice cover. Such a configuration may enable a continuous fluid flow through the DPRD, and may help to prevent or reduce the occurrence of clotting or formation of biofilm or other unwanted growths. In some embodiments the DPRD may be used to flush or clean out the shunt and/or shunt cover etc.

Reference is made to FIG. 1A, which schematically illustrates a DPRD 101 implanted in a heart 109, in accordance with an exemplary embodiment of the present invention. DPRD 101 may be implanted between two or more body lumens, for example, between a left atrium 102 and a right atrium 103 of heart 102. DPRD 101 may be implanted in other heart chambers, using different arrangements of heart chambers, and/or in or between other body lumens. In some embodiments, an opening, puncture or other structure may be formed in a wall between two body lumens, for example, in septum 105 between left atrium 102 and right atrium 103, for example, using a puncturing or cutting device mounted to the distal end of a catheter or any other suitable puncturing mechanism. DPRD 101 may then be placed in a puncture using a catheter or another suitable delivery mechanism. In some embodiments, one or more tissue fixation elements, for example, support arms 106 may support DPRD 101 at a desired position in a generated hole or puncture.

DPRD 101 may include, for example, an adjustable shunt, tube or pathway 122 to enable fluids to flow between two body lumens, organs, regions or zones etc., for example between a left atrium 102 and a right atrium 103. DPRD 101 may include a Flow Regulation Mechanism (FRM) 108 as described herein, for example a flow valve, cover, valve opening, valve stem, or lid, to enable selected modification of the parameters of shunt 122, for example, by changing the cross section of the opening of shunt 122 or the shunt's shape etc., thereby regulating the blood flow from left atrium 102 to right atrium 103. In some embodiments FRM 108 may be set in a continually ajar position to enable a continual flow of blood between the left atrium and the right atrium. For example, FRM 108 may be purposefully left ajar, to enable a selected quantity of blood to continually flow between the heart chambers. FRM 108 may be subsequently adjusted, for example, by selectively changing the size or shape of the opening, amount of blood allowed to flow through, etc., to enable the area around the opening of shunt 122 and FRM 108 to be limited and/or expanded, thereby affecting effective flow-through of shunt 122, and enabling the quantity of blood flow between the chambers to be controlled. DPRD 101 may include one or more control mechanisms 110, for example, wires, springs, cords etc. to enable FRM 108 to be passively and/or actively controlled. In one embodiment springs may be used to enable FRM 108 to act in accordance with changes in differential pressure, for example, by being pre-loaded with a selected tension, to respond in a controlled way to changes in one or more pressure thresholds.

FRM 108 may be configured to respond to selective pressure profiles, thereby providing a known pressure relief profile. For example, FRM 108 may be preset, pre-calibrated and/or pre-configured to change its setting, adjust its configuration or position, and/or change the orifice width or flow amount etc., in accordance with changes in pressure difference between the left and right atriums of the heart. FRM 108 may be continually adjustable, for example to a continuously variable setting, for example in response to environmental conditions and/or external controls. In at least these ways, DPRD 101 may provide a selected, predictable and/or guaranteed flow of fluid between two or more bodily lumens or regions etc. In some embodiments the resting or default setting, opening size, flow level or position of FRM 108 may be changed, for example, according to pre-programmed parameters and/or remote control mechanisms. In some embodiments a continuously open or ajar FRM 108 may help prevent occlusion of shunt 122.

In some embodiments, below a certain pressure or pressure differential, the valve or device may be fully closed; however in other embodiments, below a certain pressure or pressure differential, the valve may be not fully closed or slightly ajar. For example, the valve may have a minimum opening size.

In some embodiments, one or more properties of the DPRD, for example, the size of the cross-section opening of the pressure regulation device, may be dependent on the blood pressure difference between the left atrium and the right atrium. Therefore, in some embodiments, the blood flow between the left atrium and the right atrium may be influenced by the change in blood pressure difference between the left atrium and the right atrium.

A DPRD according to some embodiments of the invention may allow for a reduction in ventricular pressure by reducing pressure in an atrium of the heart.

In some embodiments, a DPRD may be used for Atrium Septum Defect (ASD) patients, for example who may not be able to tolerate a complete uncontrolled atrium closure procedure, to selectively close a hole or gap in the septum.

In some embodiments, a DPRD may be used to transfer fluid from the left atrium to the right atrium, for example, to aid a patient with pulmonary hypertension. In such cases the DPRD may be positioned with FRM 108 in the left atrium. According to some embodiments of the present invention, FRM 108 may be unidirectional or bi-directional.

In some embodiments, a plurality of DPRD's may be implanted in a wall or other structure, for example, to help provide redundancy, to implant devices with different set ranges to achieve a higher level of opening control, and/or to enable adding of additional devices. Implanting a plurality of DPRD's may enable the delivering catheter diameter to be reduced, as two or more DPRD's of a lesser diameter may be delivered.

In other embodiments FRM 108 may include a cover, lid or other suitable mechanism that may have various forms to enable partial or total closure of FRM 108. Reference is now made to FIGS. 1B-1G. In FIG. 1B FRM 108 may include two or more arms 120 which may be configured to be continuously or constantly ajar at opening 125 of shunt 122. For example, FRM 108 may be configured to remain continually at least partially detached from shunt 122, to allow a continuous flow of fluid between left atrium 102 and right atrium 103. Arms 120 may be further opened and/or closed in response to changes in pressure differences between the heart chambers. Arms 120 may be constructed from a flexible polymer or other suitable materials. Arms 120 may have rounded shapes at arm ends 130, for example, to help prevent blood stagnation.

In FIG. 1C FRM 108 may include a shunt 122, and two or more flexible membranes 135, which may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through shunt 122. For example, in the various embodiments discussed herein, a device may be set so that no matter what the pressure or pressure differential between chambers, a minimum opening size may be set or flow amount may occur. Membrane 135 may include at least one spring-type mechanism, to help expand and/or contract membrane 135, in response to changes in pressure differences between the heart chambers.

In FIG. 1D FRM 108 may include a shunt 122, and one or more flexible or spring based lid, membrane or leaflets 150, optionally connected to shunt 122 by a spring or other suitable pressure sensitive mechanism 155. In one embodiment pressure sensitive mechanism 155 may be pre-loaded to respond in a controlled way to changes in one or more pressure thresholds. Lid 150 may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through shunt 122. FRM 108 may include one or more raised areas 160, for example, thorn shaped objects or objects with other suitable shapes to help prevent lid 150 from making full contact with shunt 122.

In FIG. 1E FRM 108 may include a shunt 122, and one or more angled flexible membranes or leaflets 165, which may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through shunt 122. In one embodiment leaflets 165 may be pre-loaded with a selected tension to respond in a controlled way to changes in one or more pressure thresholds. Leaflet 165 may include at least one spring mechanism or other suitable mechanism to help close and/or open leaflet 165 in response to changes in pressure differences between the heart chambers. Leaflet 165 may include at least one magnet or electromagnet 170 or other suitable mechanism to help remotely close and/or open leaflet 165. A conducting wire 172 or other suitable mechanism may be used to activate magnet(s) or electromagnet(s) 170.

In FIG. 1F FRM 108 may include a shunt 122, and a cap, valve opening, valve stem, or other mechanism 175, which may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through shunt 122. Cap 175 may be coupled to a spring 177 or other suitable pressure sensitive mechanism. In one embodiment spring 177 may be pre-loaded with a selected tension to respond in a controlled way to changes in one or more pressure thresholds. FRM 108 may include one or more cap motion limiters 179. FRM 108 may include a fixed polarized magnet 181 and an electromagnetic coil 183 that includes one or more conductors 185. Cap 175 may be opened and/or closed in response to changes in pressure differences between the heart chambers and/or by remotely activating magnet 181 and/or magnetic coil 183. For example, when magnet 181 is activated cap 175 may be further opened, and when coil 183 is activated cap 175 may be further closed.

As shown in FIG. 1G FRM 108 may include a shunt 122, and a cap 175, which may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through tube 122. Cap 175 may be connected to shunt 122 by a connection arm 185. Cap 175 may include cuts, slots, grooves or slits etc. 187 to enable a continuous blood flow through shunt 122. Slots 187 may be of different sizes, depths, widths, or densities, which may help dictate whether various areas of cap 175 are to be stronger and less flexible or weaker and more flexible, and may therefore respond differently to changes in pressure differences between the bodily lumens. For example, in an area where there are more or deeper incursions the area may be relatively weak and flexible, thereby allowing cap 175 to be at least partially opened by a relatively low pressure blood flow through shunt 122. In an area where there are fewer and/or more superficial incursions the area may be relatively strong or less flexible, thereby only allowing cap 175 to be at least partially opened by a relatively high pressure blood flow through shunt 122.

As shown in FIGS. 1H and 1I FRM 108 may include a shunt 122, and a cap 175, which may be configured to be constantly ajar at opening 125 to enable a continuous blood flow through shunt 122. Cap 175 may be coupled to a spring 190 or other suitable pressure sensitive mechanism. Spring 190 and cap 175 may be connected to a piston or pump mechanism 192. As can be seen in FIG. 1I, cap 175 may be opened and/or closed in response to changes in pressure differences between the heart chambers and/or by piston 192 activating spring 190 to extend and/or distend cap 175, thereby changing the size of opening(s) 125.

According to some embodiments of the present invention, the usage of DPRD 101 may enable generation of a pressure curve related to the relationship between the change in pressure difference between two lumens, the flow through the flow control mechanism and the orifice area. Any required or selected design parameters may be used. Reference is now made to FIG. 1J, which illustrates an example of such a pressure curve. As can be seen in FIG. 1J, below a pressure differential of 12 mmHg, the opening or orifice size may be relatively stable, and flow may be influenced substantially by the pressure difference. When pressure difference rises above approximately 12 mmHg until approximately 20 mmHg the flow may increase at a higher rate, as it may now be influenced by both the increase in orifice area and the increase in pressure difference. When pressure difference rises above approximately 20 mmHg the flow rate increase at a slower rate, since the orifice area may have already reached its maximum cross-section, and the flow may be influenced substantially by the pressure difference. Pressure differences and/or may be effected by linear and/or non-linear changes in the orifice area. Other pressure difference, flow and/or orifice area levels, relationships, and interrelationships may be used, as may other parameters, variables, minimum and maximum limits etc.

Reference is made to FIGS. 2A and 2B, which schematically illustrate a cross-section view and a side view, respectively, of an adjustable DPRD 201 in accordance with an exemplary embodiment of the invention. DPRD 201 may include, for example, a frame 220 connected to one or more support arms, e.g., arms 211-216. Frame 220 may include, for example, a flexible fixation frame, ring or tube. Frame 220 may be formed from a flexible material, for example, a flexible metal, super elastic alloy, and/or a shape-memory material, e.g., Nitinol or other suitable materials.

Although DPRD 201 is described herein as having six arms or appendages 211-216, for exemplary purposes, embodiments of the present invention are not limited in this regard and may include a different number of arms, for example, one arm, two arms, ten arms, or the like.

Arms or appendages 211-216 may be flexible and/or may be pre-shaped to achieve a desired functionality. For example, arms 211-216 may be folded during an insertion process, e.g., inside a suitable delivery tube. In some embodiments, arms 211-216 may be formed of a super elastic material, for example, a Shape-Memory Alloy (SMA), e.g., nickel-titanium (NiTi) alloy. Other suitable materials may include, for example, metals, stainless steel, and/or other suitable materials. At least part of arms 211-216 or other selected elements of DPRD 201 may be coated and/or textured to increase their bio-compatibility and/or to increase the degree to which these elements may become selectively endothelialized, as may be desired in some implantation conditions.

DPRD 201 may include, for example, a FRM 250, for example, including a cover, valve opening, valve stem, or other flow regulation mechanism with one or more pre-set positions, to selectively cover an orifice resulting from the deployment of DPRD 201. FRM is described in detail below.

As illustrated schematically in FIG. 2B, DPRD 201 may have two sides, which may be referred to herein as a proximal side 251 and a distal side 252, respectively. For example, DPRD 201 may be implanted in heart 109, such that the proximal side 251 of DPRD 201 may face the right atrium 103, and the distal side 252 of DPRD 201 may face the left atrium 102. Other orientations of sides 251 and 252 may be used, as may other numbers of sides.

In some embodiments, the distal side 252 of DPRD 201 may be connected to a distal set of arms or appendages, e.g., arms 211-213, and the proximal side 251 of DPRD 201 may be connected to a proximal set of arms or appendages, e.g., arms 214-216. Thus, when DPRD 201 is implanted in heart 109, the distal set of arms 211-213 may first be discharged in the left atrium 102, e.g., to the right of septum 105 in FIG. 1, thus supporting DPRD 201 to the left side, from the patient's perspective, of septum 105. Then, as the insertion of DPRD 201 is completed, e.g., by retracting a catheter or delivery tube carrying DPRD 201, the proximal set of arms 214-216 may be discharged in the right atrium 103, e.g., to the left of septum 105 in FIG. 1, thus supporting the right side, from the patient's perspective, of septum 105. In this manner, arms 211-216 may support frame 220 of DPRD 201 at a desired position between the left atrium 102 and the right atrium 103.

Reference is now made to FIG. 3, which schematically illustrates a DPRD 301 in accordance with another exemplary embodiment of the present invention. DPRD 301 may include, for example, a frame 302 connected to one or more arms or appendages, for example, arms 303 and 304.

Frame 302 may include, for example, a flexible fixation frame formed from a flexible material, for example, a flexible metal, e.g., Nitinol or Nitinol wire. Frame 302 may have a generally helical shape, for example, as schematically illustrated in FIG. 3, and may be integrally formed with curved arms 303 and 304 at either end of frame 302, as schematically illustrated in FIG. 3. Other suitable shapes may be used. Arms 303 and 304 may be flexible and may be pre-shaped to achieve a desired functionality. For example, arms 303 and 304 may be folded during an insertion process, e.g., inside a suitable delivery tube, in order to be subsequently discharged for positioning the frame 302 in a puncture. In accordance with some exemplary embodiments of the present invention, DPRD 301 may include a FRM 350, for example, a FRM as detailed herein.

Reference is also made to FIG. 4, which schematically illustrates a DPRD 401 including a DPRD 450 in accordance with an exemplary embodiment of the invention. DPRD 450 may be an example of FRM 250 or FRM 350. For exemplary purposes only, DPRD 450 is shown in conjunction with a DPRD 401 which may be similar to DPRD 201, although DPRD 450 may be used in conjunction with DPRD 301 or any other suitable shunts or medical devices.

DPRD 450 may include, for example, a disk 432 connected to a ring 431 by a spring 433. Disk 432 may be formed of a bio-compatible material, for example, pyrolitic carbon or stainless steel. Spring 433 may include one or more swivel springs, twisting springs, or any other spring elements, which may hold disk 432 inside ring 431 when there is substantially no pressure differential between the two sides of DPRD 401, e.g., between the proximal side 251 and the distal side 252 of DPRD 201 of FIG. 2B.

In response to a pressure differential between the two sides of DPRD 401, disk 432 may move away from the atrium having the relatively higher pressure, typically the left atrium, bending spring 433 which may apply a counterforce to the movement of disk 432, thereby opening and/or enlarging a cavity through which blood may pass. The counterforce applied by spring 433 may depend on the pressure differential between the two sides of DPRD 401, for example when the pressure in an atrium forces spring 433 to contract, such that the higher the pressure differential across DPRD 401, the larger the opening to allow relief of such pressure differential by flow from the high pressure side to the low pressure side. In this manner, the pressure differential between the proximal and distal sides of DPRD 401 may be controlled in accordance with one or more selected levels. In some embodiments the various configurations for DPRDs described herein may allow for opening sizes or flow rates that vary continuously with pressure differentials.

It will be appreciated that when there is substantially no pressure difference between the two sides of DPRD 401, or when the pressure difference is relatively small, disk 432 may be fully closed, or in addition may not entirely block the flow of blood through DPRD 450, for example, through the area between disk 432 and ring 431. For example, disk 432 may be selectively set with a gap between ring 431 and disk 432, such that disk 432 may function as a leaking valve to enable blood to continuously flow through a puncture. The continual freedom of flow across DPRD 401 may, for example, prevent blood clotting and/or thrombus formation in and/or around disk 432.

In some embodiments, ring 432 may be asymmetric, for example, ring 432 may have a relatively wider upper section 451 and a relatively narrower lower section 452. This may allow, for example, blood passage at a relatively small flow-rate during tilting of disk 432 under increased pressure, until disk 432 bends beyond the upper section of ring 431, thereby providing a pressure or pressure differential threshold at which the valve opens or begins to open, to increase the blood flow cross-section through the vessel. The pressure threshold may be a continual (e.g., infinitely variable) set of pressure points at which the valve opens or allows a pressure flow in accordance with the pressure. For example, the valve may remain closed or slightly ajar until a certain pressure, then above that pressure open continually until an upper pressure is reached, at which the valve is fully open. It is noted that an asymmetric ring 432 or other asymmetric components may be used to achieve similar functionality in various other FRMs, DPRDs, shunts and/or devices in accordance with embodiments of the present invention.

In some embodiments, ring 431 may be formed of, for example, a suitable metal. In some embodiments, ring 431 may be integrated within frame 220, or ring 431 and frame 220 may be implemented using an integrated ring-frame component. Ring 431 and/or frame 220 may be formed of a suitable wire or tube. Ring 431 and/or arms 211-216 may be formed of a suitable wire or tube, e.g., the same wire or tube and/or the same material.

Reference is also made to FIG. 5, which schematically illustrates DPRD 401 implanted in heart 109, incorporating DPRD 450 in an open state in accordance with an exemplary embodiment of the present invention. A pressure difference may exist between left atrium 102 and right atrium 103, for example, the pressure in left atrium 102 may be larger than the pressure in right atrium 103. The pressure difference may cause disk 432 to move towards right atrium 103 and bend the spring 433, thereby creating an enlarged opening through which more blood may flow from left atrium 102 to right atrium 103. As the blood flows towards right atrium 103, the pressure in left atrium 102 may decrease and the pressure in the right atrium may increase, thereby reducing the pressure difference between the left atrium 102 and the right atrium 103, and allowing spring 433 to pull back disk 432 towards a closed or substantially closed position. Other mechanisms to enable disk 432 to move may be used.

FIG. 6 schematically illustrates a DPRD 650 in accordance with another exemplary embodiment of the invention. DPRD 650 may be an example of FRM 108, FRM 250 or FRM 350. DPRD 650 may include, for example, ring 431 and a pre-shaped wire 634. Wire 634 may include a flexible metal wire, for example, formed of Nitinol or other suitable materials. In one embodiment wire 634 may be curved to a shape of a horse-shoe or tongue or another suitable shape. In some embodiments, an end of wire 634 may be attached to ring 431, or wire 634 and ring 431 may be formed of the same wire, tube or other suitable material.

Wire 634 may be covered by or connected to a cover or sheet 635, which may include, for example, a flat sheet of bio-compatible material, for example, a biological tissue material used in conjunction with artificial valve leaflets. Sheet 635 may be attached to wire 634, for example, using one or more stitches 636.

DPRD 650 may be included in, for example, DPRD 201 or DPRD 301, implanted in heart 109. A pressure difference may exist between left atrium 102 and right atrium 103, for example, the pressure in left atrium 102 may be larger than the pressure in right atrium 103. The pressure difference may cause sheet 635 to move, utilizing the elasticity of wire 634, thereby creating a cavity through which blood may flow from left atrium 102 to right atrium 103. As the blood flows in that direction, the pressure in left atrium 102 may decrease and the pressure in the right atrium may increase, thereby reducing the pressure difference between the left atrium 102 and the right atrium 103, and allowing sheet 635 to move back towards a closed or substantially closed position or towards a position wherein sheet 635 is in a marginally opened position.

It is noted that when there is no pressure difference between the left atrium 102 and the right atrium 103, or when the pressure difference is relatively small, sheet 635 may not entirely block a blood flow through DPRD 650, for example, through the area around sheet 635, or between sheet 635 and ring 431. This may, for example, prevent blood clotting and/or thrombus formation in and/or around sheet 635 or DPRD 650. However, as with the other configurations discussed herein, in other embodiments, the opening or valve may be completely closed at certain pressure differentials.

FIG. 7 schematically illustrates a FRM 750 in accordance with another exemplary embodiment of the invention. FRM 750 may include, for example, ring 431 connected to a cone 737 using one or more springs 738. Cone 737 may be positioned inside ring 431, and may be formed of, for example, a bio-compatible material, e.g., pyrolitic carbon or stainless steel. Cone 737 may have a suitable shape, for example, rectangular, square-shaped, circular, oval, trapezoid-shaped, cone-shaped, or other suitable shapes.

FRM 750 may be included in a shunt, e.g., DPRD 201 or DPRD 301, implanted in heart 109. Springs 738 may include one or more compression springs, and may hold cone 737 inside ring 431, for example, when substantially no pressure difference exists between left atrium 102 and right atrium 103.

When a pressure difference exists between left atrium 102 and right atrium 103, for example, when the pressure in left atrium 102 is larger than the pressure in right atrium 103, FRM 750 may allow blood flow from left atrium 102 to right atrium 103. The pressure difference may cause cone 737 to move back against springs 738, thereby opening or enlarging a cavity through which blood may flow from left atrium 102 to right atrium 103. As the blood flows in that direction, the pressure in left atrium 102 may decrease and the pressure in the right atrium may increase, thereby reducing the pressure difference between the left atrium 102 and the right atrium 103, and allowing cone 737 to move back towards a closed or substantially closed position.

It is noted that when there is no pressure difference between the left atrium 102 and the right atrium 103, or when the pressure difference is relatively small, cone 737 may not entirely block a blood flow through FRM 750, for example, through the area around cone 737, or between cone 737 and ring 431. This may, for example, prevent blood clotting and/or thrombus formation in and/or around cone 737 or FRM 750.

FIG. 8 schematically illustrates a FRM 850 in accordance with another exemplary embodiment of the invention. FRM 850 may include, for example, a flexible valve 839 connected to and positioned inside ring 431. Valve 839 may be formed of, for example, a bio-compatible material, e.g., polyurethane or silicone. Valve 839 may be attached to ring 431, for example, by gluing or stitching a base 840 of valve 839 inside ring 431. Valve 839 may include one or more leaflets, for example, leaflets 841 and 842 able to move and create or enlarge an opening 843. In some embodiments, the size of opening 843 may be in relation to a pressure applied to leaflets 841 and 842.

FRM 850 may be included in a shunt, tube or conduit, e.g., DPRD 201 or DPRD 301, implanted in heart 109. When a pressure difference exists between left atrium 102 and right atrium 103, for example, when the pressure in left atrium 102 is larger than the pressure in right atrium 103, FRM 850 may allow blood flow from left atrium 102 to right atrium 103. The pressure difference may stretch, spread or push leaflets 841 and/or 842, thereby increasing the distance between them and enlarging the opening 843, through which blood may flow from left atrium 102 to right atrium 103. As the blood flows in that direction, the pressure in left atrium 102 may decrease and the pressure in the right atrium may increase, thereby reducing the pressure difference between the left atrium 102 and the right atrium 103, and allowing leaflets 841 and/or 843 to move back towards a closed or substantially closed position.

It is noted that when there is no pressure difference between the left atrium 102 and the right atrium 103, or when the pressure difference is relatively small, valve 839 and leaflets 841 and 842 may not entirely block a blood flow through FRM 850, for example, through the opening 843. This may, for example, prevent blood clotting and/or thrombus formation in and/or around valve 839 or FRM 850.

FIG. 9 schematically illustrates a DPRD 950 within heart 109, in accordance with another exemplary embodiment of the invention. DPRD 950 may include a plurality of balloons or sacs inter-connected through one or more tubes, for example, a non-compliant balloon 943 connected through a tube 944 to a compliant balloon 945. The non-compliant balloon 943 may be placed in the left atrium 102 and/or in a puncture, and the compliant balloon 945 may be placed in the right atrium 103. In some embodiments, balloons 943 and/or 945 may be may be attached to a ring (e.g., ring 431). In some embodiments balloons 943 and/or 945 may contain a liquid 920.

Liquid 920 may flow from balloon 943 to balloon 945 or vice versa, for example, in relation to a pressure difference between the left atrium 102 and the right atrium 103. For example, when there is a relatively larger pressure in the left atrium 102, liquid 920 may flow from non-compliant balloon 943 through tube 944 to compliant balloon 945, thereby deflating the non-compliant balloon 943 and inflating the compliant balloon 945. It is noted that compliant balloon 945 may be more flexible than non-compliant balloon 943, allowing the compliant balloon 945 to act as a spring mechanism to control the deflating of the non-compliant balloon 943.

FIG. 10 schematically illustrates a DPRD 1050 in accordance with another exemplary embodiment of the invention. DPRD 1050 may include, for example, ring 431 and a flexible disk 1046 having a hole 1047. In some embodiments, hole 1047 may be substantially circular and may be located, for example, substantially in the center of flexible disk 1046. Flexible disk 1046 may be formed of, for example, a flexible polymetric material, e.g., silicone rubber or polyurethane.

DPRD 1050 may be implanted in heart 109, and hole 1047 may change its diameter in relation to a pressure difference between the left atrium 102 and the right atrium 103. For example, the pressure difference may push backwards or stretch the flexible disk 1046, thereby enlarging the hole 1047 and allowing a larger area through which blood may flow from the left atrium 102 to the right atrium 103.

It is noted that when there is no pressure difference between the left atrium 102 and the right atrium 103, or when the pressure difference is relatively small, hole 1047 may still be open and may have a relatively small diameter, and flexible disk 1046 may not entirely block a blood flow through DPRD 1050. This may, for example, prevent blood clotting and/or thrombus formation in and/or around DPRD 1050.

FIG. 11 schematically illustrates a DPRD 1150 in accordance with another exemplary embodiment of the invention. DPRD 1150 may include, for example a balloon or sac 1148 such as a non-compliant balloon containing a liquid 1120. The balloon 1148 may be placed or connected inside a ring 1131, which may include, for example, a ring similar to ring 431 and/or a frame. A tube 1149 may connect balloon 1148 to a reservoir 1155, which may include one or more pistons 1151 able to move against one or more compression springs 1152. Springs 1152 may be formed of, for example, metal or a suitable elastic material.

DPRD 1150 may be implanted in heart 109, and balloon 1148 may change its volume in relation to a pressure difference between the left atrium 102 and the right atrium 103. For example, the pressure difference may push or deflate the balloon 1148, thereby causing liquid 1120 to flow from balloon 1148 to reservoir 1155. This may create or enlarge an opening inside ring 1131, through which blood may flow from the left atrium 102 to the right atrium 103.

FIG. 12 schematically illustrates a DPRD 1250 in accordance with another exemplary embodiment of the invention. DPRD 1250 may include, for example a balloon 1148 such as a non-compliant balloon containing a liquid 1120. The balloon 1148 may be placed or connected inside a ring 1131, which may include, for example, a ring similar to ring 431 and/or a frame. A tube 1149 may connect balloon 1148 to a reservoir 1155, which may include one or more pistons 1151 able to move. The piston 1151 may be moved, for example, using a motor 1153, which may include an electric motor, e.g., a step motor or other suitable motors. Motor 1153 may move, push or pull pistons 1151, thereby causing liquid 1120 to flow from balloon 1148 to reservoir 1155 or vice versa. This may change the volume of balloon 1148, thereby increasing or decreasing a size of an opening inside ring 1131, through which blood may flow from the left atrium 102 to the right atrium 103.

According to some embodiments of the present invention, the DPRD may be actively controlled, for example, by a patient or medical service provider. In one embodiment DPRD may be operated using external and/or manually provided instructions. For example, motor 1153 may operate in accordance with external and/or manually provided instructions. Additionally or alternatively, motor 1153 may operate in relation to a pressure difference between the left atrium 102 and the right atrium 103. For example, a pressure-dependent close loop 1260 may be used, incorporating one or more pressure transducers 1254. The pressure transducers 1254 may measure an absolute pressure in one or more heart chambers, for example, in left atrium 102 and/or right atrium 103, or may measure a differential pressure between two heart chambers, for example, between left atrium 102 and right atrium 103. Based upon the pressure information, motor 1153 may operate and move, push or pull the pistons 1151.

In other embodiments DPRD may be remotely operated using one or more of electric mechanisms, mechanical mechanisms, wireless mechanisms, pneumatic mechanisms or other suitable mechanisms. For example, a wire, line, spring, pin, cable, hook, latch, motor or magnet may be connected to the DPRD to enable the DPRD to be remotely controlled by a patient and/or medical service provider. As can be seen with reference to FIG. 13A at least one line or control lead 1320 may connect DPRD 1300 to a control mechanism 1310, for example, a control box. For example, control lead 1320 may exit vein 1330 through a puncture or hole 1335. Control mechanism 1310 may include, for example, a mechanical interface, electrical interface, pull/push wire, spring, magnet or other suitable elements or mechanisms to enable DPRD 1300 to be remotely controlled.

Control mechanism 1310 may be a micro mechanism that may be placed internally or externally, for example, it may be sown into tissue under a patient's skin, to provide external access for a medical service provider, or it may be placed internally in proximity to a location that may be accessed by a medical service provider with a minimally invasive technique.

In one embodiment DPRD 1300 may be controlled wirelessly from an external ‘transmitting’ unit. For example, control signals may be delivered from outside a patient's body using telemetry, localized RF radiation, localized Ultrasound radiation, external magnetic field, localized heating and other suitable means of generating signals. In such an embodiment DPRD 1300 may include a ‘receiving’ unit. The receiving unit may include an internal power source (e.g., a battery), or may receive its energizing power from the control signal or other transmitted signals. The receiving unit may be coupled to an external power source, for example, via an implanted plug, or may be directly connected to DPRD 1300 on a temporary basis (e.g., at the doctor's office), were the implanted plug may relay command signals and/or power to activate DPRD 1300.

Reference is now made to FIG. 13B, which indicates an example of a control mechanism 1310 being positioned under the skin surface 1360. In one example control lead 1320 may be accessed by entering the patient using a conventional needle or syringe 1365, for example by making a small incision. Control lead(s) 1320 may be controlled externally or internally to enable DPRD 1300 to be controlled. In some embodiments control lead(s) 1320 may operate within a tube, for example a silicon pressurized tube 1370. Control mechanism 1310 may include a remote valve opening/closing mechanism, for example, to enable monitoring of heart pressure, monitoring of DPRD functioning etc. In one example, control mechanism 1310 may be used to monitor blood flow changes in response to valve positioning. Control mechanism 1310 may enable manual reduction of heart pressure or in blood pressure in certain chambers or the heart in the case of clinical need. Control mechanism 1310 may enable flushing or cleaning of DPRD 1300 at selected intervals, for example, by increasing internal blood pressure or fluid pressure. In other embodiments flushing or cleaning may be enabled using a flushing or cleaning fluid, for example, saline solution that may be entered into control lead 1320 at a selected pressure to cause the orifice to be cleaned or flushed. Such cleaning may help in reducing undesired growth, infections etc. associated with DPRD 1300.

Control mechanism 1310 may be coated with one or more substances to prevent thrombosis or other conditions. DPRD 1300 may include spikes, thorns or other suitable mechanisms to prevent a FRM from being in full contact with a shunt, or to ensure only minimal contact between a FRM and a shunt. Control mechanism 1310 may enable parts of DPRD 1300 to be remotely replaced, cleaned, serviced or otherwise manipulated. Control mechanism 1310 may enable a pre-configured or designed leak to be remotely opened, closed, or otherwise changed in accordance with clinical requirements. Control mechanism 1310 may enable blocking up of the DPRD's orifice or cavity, for example, by remotely placing a plug in the orifice to cease functioning of the DPRD. One or more of the above qualities may enable a health service provider to remotely control the functioning of DPRD 1300.

In one embodiment, as can be seen with reference to FIG. 13C, control mechanism 1310 may include one or more push knobs 1340 or other suitable controls or mechanisms that may be controlled using a finger or other suitable implement. For example, the various push knobs 1340 may be pushed individually, simultaneously and/or in various other combinations to achieve a desired effect in DPRD 1300. In one embodiment control mechanism 1310 may include, for example, one or more rods or electric conductors 1350 to help control DPRD 1300. In one embodiment control mechanism 1310 may include, for example, one or more security mechanisms 1345, for example, a locking button to help prevent non-required changes from being made to the operation of DPRD 1300. In other embodiments control mechanism 1310 may include one or more springs or other suitable control mechanisms coupled to rod 1350 and DPRD 1300.

In one embodiment, as can be seen with reference to FIG. 13D, control mechanism 1310 may be used to control DPRD 1300, for example using one or more rods or wires 1375 etc., optionally operating within tube 1370. DPRD 1300 may include a cover 1377, for example, flexible or non-flexible cover, which may be left constantly ajar, for example, to form gap 1379. In one embodiment cover 1377 may be constructed from a rigid material and may be assembled or connected in a rigid manner to a locking mechanism 1380. Once cover 1377 has been set in a selected position by locking mechanism 1380, it may remain stable, for example, not being affected by blood pressure changes, until cover 1377 is re-positioned. In such a case, cover 1377 may only be adjusted by intentional and controlled actions using control mechanism 1310, for example, wires 1375 using signals, or other suitable communication links.

Locking mechanism 1380 may enable cover 1377 to be remotely set in one or more positions. Locking mechanism 1380 may include, for example, one or more of a spring, latch, lever, notch, slot, hook, slide or other suitable locking mechanism(s). For example, position # 1 may be a lower position, for example where the hook 1325 fastens onto the catching mechanism 1332 as indicated; position # 2 may be a medium position, for example where the hook 1325 fastens onto the catching mechanism 1333; position # 3 may be a higher position for example where the hook 1325 fastens onto the catching mechanism 1334. Other settings, opening sizes, flow levels, positions and numbers of positions may be used. Control mechanism 1310 may include security features, for example, to help prevent unauthorized personnel from activating DPRD 1300 (e.g., special tools and magnets, coded sequence, password etc).

In one embodiment, as can be seen with reference to FIG. 13E, control mechanism 1310 may be used to control DPRD 1300, for example using an auxiliary hydraulic system. DPRD 1300 may be connected to the hydraulic system, for example, via one or more tubes 1390 that may help control the pressures and/or flow rates of fluids delivered through DPRD 1390. DPRD 1390 may be connected to the hydraulic system when required, or may be permanently attached to the hydraulic system. In one embodiment tubing 1390 may increase the fluid pressure in DPRD 1300, for example, to provide significant force on or inside the shunt. Tubing 1390 may additionally or alternatively be used for “maintenance”, for example, by forcing liquid through the shunt, for example, via shunt base 1392, to flush, clean and/or lubricate the shunt and/or FRM 1396, and/or to release moving parts in DPRD 1300 in order to keep DPRD 1300 in a required operating condition or state. In one example, a substance (e.g., saline solution) may be injected and/or extracted to/from tubing 1390 to change the pressure at base 1392 and thereby activate piston diaphragm 1394. Piston diaphragm 1394 may be extended and/or distended thereby causing FRM 1396 to be manipulated, for example, to open and/or close FRM 1396, to allow fluid to selectively flow through DPRD 1300. Tube 1390 may be connectable to tube 1320 (see FIGS. 13A and 13B) and/or to a needle 1366 or other suitable device for penetrating a patient's skin to connect to tube 1390. In one embodiment the hydraulic mechanism may be used after deployment of DPRD 1300 in the body, for example to verify operability of DPRD 1300. In a further embodiment the hydraulic mechanism may be used when checking DPRG operability following deployment of DPRD 1300 in the body.

It will be appreciated that some embodiments of the present invention may use one or more threshold values, pre-defined parameters, conditions and/or criteria, for example, to trigger an activation or a de-activation of a shunt, a DPRD or a FRM.

Various suitable techniques for implanting a device according to an embodiment of the invention may be used. According to some embodiments, the pressure regulation device may be delivered and implanted in a patient's body using a minimally invasive procedure, for example, using percutaneous delivery. In such an example, the device may be mounted on a catheter delivery system and inserted to the body via small incision. Once the device is in the correct location inside the body, it may be deployed by an operator, expanded and locked in place. A device that is delivered on a catheter may be, for example, contracted or folded into a small dimension, and the device may self-expand upon deployment. In other embodiments the pressure regulation may be delivered using invasive surgery, for example where a surgeon makes a larger opening in the body in order to achieve more direct contact with the device implantation location.

In one embodiment of the present invention, as described in embodiments in U.S. patent application Ser. No. 09/839,643, entitled “METHOD AND APPARATUS FOR REDUCING LOCALIZED CIRCULATORY SYSTEM PRESSURE” and filed on 20 Apr. 2001, in particular in FIGS. 3-5, a transseptal needle set may be advanced toward the wall of the right atrial septum. Access may be made from the femoral vein with the apparatus being advanced through the inferior vena cava and into the right atrium. Once transseptal puncture has been achieved, a guidewire may be exchanged for a needle component and then passed into the left atrium. The process of securing catheter access to the left atrium by way of a transseptal puncture is known in the art. After a transseptal sheath is positioned in the left atrium, as describe above, the placement of a shunt made in accordance with embodiments of the present invention may be initiated.

The dilator and wire may subsequently be withdrawn from the sheath that may now extend from the femoral vein access point in the patient's groin to the left atrium, traversing the femoral vein, the illiac vein, the inferior vena cava, the right atrium, and the atrial septum etc. The delivery catheter may be passed through the sheath while under fluoroscopic visualization. Radiopaque markers may be provided on this catheter as well as the sheath in order to locate specific points. The delivery catheter may be carefully and slowly advanced so that the most distal portion of the left-atrial fixation element is emitted from the distal opening of the catheter and into the chamber of the left atrium. The fixation elements may be formed from a spring-like material and/or may be a super-elastic of shape-memory alloy, so that as it leaves the constraint provided by the inner area of the delivery catheter, it reforms into its pre-configured fully formed shape. The assembly of the sheath and the delivery catheter may then slowly be retracted en bloc so as to withdraw the fixation elements towards the atrial septum. The physician may stop this retraction when it becomes apparent by fluoroscopic visualization as well as by tactile feedback that the fixation element has become seated against the atrial septum. At that point, the sheath alone may be retracted, uncovering the shunt and positioning it within the opening that has been created within the atrial septum. The sheath may then be further retracted, allowing the right-atrial fixation element to reform into its fully formed shape. The entire shunt assembly or DPRD may then be detached from the delivery catheter system. The DPRD may be controlled within the delivery catheter by means of long controller wire that has independent translational control within the catheter area. This attachment may be formed by any conventional method, e.g., a solder or adhesive or the like that may mechanically detach at a prescribed tension level, that level being exceeded by the physician at this point in the procedure by firmly retracting the controller wire. Other methods of deployment of DPRD and/or FRM may be used.

Reference is now made to FIG. 14, which illustrates a method of delivering a DPRD and/or a FRM into a body area, for example, the septum of the heart between the left and right atrium, according to some embodiments of the present invention. Implantation of a device in the septum may involve one or more of the following processes: a) identifying the precise site for implantation; b) aiming the device toward the selected site; and c) ensuring accuracy and integrity of the implantation. The ideal implantation position may be chosen, for example, by a medical professional, for example, by imaging the septum and analyzing the septum anatomy (e.g., by TEE). The aiming may include identifying the precise device delivery tool location using known tools for ‘mapping’ the septum site. Markers may be added to the delivery tools and devices (e.g., gold markers). Once the position has been identified and the device has been deployed, the medical professional may check and test the device installation, optionally before full retrieval of the delivery system. For example, the medical professional may use direct contact such as physically challenging or pulling the entire device (e.g., by pulling gently on the device to ensure proper anchoring). The anchoring may be tested by non-contact means (e.g., using electromagnetic imaging, Echo, x-ray, angiography with contrast material etc.).

At block 140 a DPRD may be implanted between two or more chambers, lumens, organs, regions, zones etc. in a body, for example, using a catheter. At block 141 a FRM may be deployed in a selected setting or position, for example, to enable a continuous flow of fluid between two or more lumens, and to be selectively activated or de-activated in accordance with changes in pressure differences between the lumens. At block 142 the FRM may be controlled (e.g., passively) in response to changes in pressure differences between the lumens, for example, FRM may be further opened and/or closed in response to a pressure change. Optionally, at block 143 the DPRD and/or FRM may be remotely controlled to help control the flow of fluids between the lumens. In some embodiments the remote control of the DPRD and/or FRM may enable cleaning the DPRD and/or FRM, disabling the DPRD and/or FRM, changing elements of the DPRD and/or FRM etc. Any combination of the above steps may be implemented. Further, other steps or series of steps may be used.

The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be appreciated by persons skilled in the art that many modifications, variations, substitutions, changes, and equivalents are possible in light of the above teaching. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. 

1. A differential pressure regulating device, the device comprising: a shunt being for positioning in the septum of a heart between a left atrium and a right atrium, to enable fluids to flow between said left atrium and said right atrium, and an adjustable flow regulating mechanism configured for setting a blood flow rate through said shunt as function of a pressure differential between said left atrium and said right atrium such that an increase in said pressure differential within a first pressure differential range results in a different blood flow rate increase through said shunt as compared to an identical increase in said pressure differential within a second pressure differential range; wherein said first pressure differential range is approximately 12-20 mmHg.
 2. The pressure regulating device of claim 1, wherein said shunt is configured for protruding into said left atrium and/or said right atrium when positioned within said septum.
 3. The pressure regulating device of claim 1, comprising a control mechanism to remotely control said flow regulating mechanism.
 4. The pressure regulating device of claim 3, wherein said control mechanism includes one or more mechanisms selected from the group consisting of: wires, lines, springs, pins, cables, magnets, hooks, latches, electric mechanisms, pressure transducers, telemetry mechanisms, wireless mechanisms, pneumatic mechanisms, and motors.
 5. The pressure regulating device of claim 1, wherein said second differential range has an upper limit of approximately 12 mmHg or a lower limit of approximately 20 mmHg.
 6. The differential pressure regulating device, of claim 1 further comprising a control mechanism to be coupled to said adjustable flow regulating mechanism, said control mechanism being remotely activatable to adjust said adjustable flow regulating mechanism.
 7. The pressure regulating device of claim 6, wherein said control mechanism includes one or more mechanisms selected from the group consisting of one or more wires, lines, springs, pins, cables, magnets, hooks, latches, electric mechanisms, pressure transducers, wireless mechanisms, telemetry mechanisms, pneumatic mechanisms, and motors.
 8. A method of regulating pressure in a heart chamber comprising: implanting a shunt in a septum between a left atrium and a right atrium of a heart in a body of a subject in need, wherein said shunt comprises an adjustable flow regulating mechanism configured for setting a blood flow rate within said shunt as function of a pressure differential between said left atrium and said right atrium; and deploying said adjustable flow regulating mechanism, thereby regulating pressure in said left atrium; wherein said adjustable flow regulating mechanism sets a blood flow rate through said shunt as function of a pressure differential between said left atrium and said right atrium such that an increase in said pressure differential within a first pressure differential range results in a higher blood flow rate increase through said shunt as compared to an identical increase in said pressure differential within a second pressure differential range.
 9. The pressure control method of claim 8, comprising remotely controlling said adjustable flow regulating mechanism.
 10. A method of regulating pressure in a heart chamber comprising: implanting a shunt in a septum between a left atrium and a right atrium of a heart in a body of a subject in need, wherein said shunt comprises a valve configured for setting a blood flow rate within said shunt as function of a pressure differential between said left atrium and said right atrium; and deploying said valve, thereby regulating pressure in said left atrium; wherein said valve sets a blood flow rate through said shunt as function of a pressure differential between said left atrium and said right atrium such that an increase in said pressure differential within a first pressure differential range results in a higher blood flow rate increase through said shunt as compared to an identical increase in said pressure differential within a second pressure differential range. 